From 44418ef82342a1533f234e6a2b743cfa5076dddd Mon Sep 17 00:00:00 2001
From: Yahor Berdnikau <egorr.berd@gmail.com>
Date: Mon, 8 Mar 2021 22:14:28 +0100
Subject: [PATCH] Fix NPE in NoConsecutiveBlankLinesRule.

---
 .../standard/NoConsecutiveBlankLinesRule.kt      |  6 ++++--
 .../standard/NoConsecutiveBlankLinesRuleTest.kt  | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRule.kt
index 0ac2c2c9fe..ce95cb49bd 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRule.kt
@@ -9,14 +9,16 @@ import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.PsiWhiteSpace
 import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafPsiElement
 
-class NoConsecutiveBlankLinesRule : Rule("no-consecutive-blank-lines") {
+public class NoConsecutiveBlankLinesRule : Rule("no-consecutive-blank-lines") {
 
     override fun visit(
         node: ASTNode,
         autoCorrect: Boolean,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
     ) {
-        if (node is PsiWhiteSpace) {
+        if (node is PsiWhiteSpace &&
+            node.prevSibling != null
+        ) {
             val text = node.getText()
             val lfcount = text.count { it == '\n' }
             if (lfcount < 2) {
diff --git a/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRuleTest.kt b/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRuleTest.kt
index fc894e69bd..7f105b852e 100644
--- a/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRuleTest.kt
+++ b/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/NoConsecutiveBlankLinesRuleTest.kt
@@ -207,4 +207,20 @@ class NoConsecutiveBlankLinesRuleTest {
             )
         ).isEmpty()
     }
+
+    @Test
+    fun `should not raise NPE on linting Kotlin script file`() {
+        assertThat(
+            NoConsecutiveBlankLinesRule().lint(
+                """
+                import java.net.URI
+
+                plugins {
+                    `java-library`
+                }
+                """.trimIndent(),
+                script = true
+            )
+        ).isEmpty()
+    }
 }